SAN ANTONIO - Federal health experts are warning people of a growing danger in the water: a parasitic infection that spreads easily and is hard to kill.

It's called cryptosporidium, also known as "crypto." According to the Centers for Disease Control and Prevention, outbreaks of crypto are on the rise, doubling between 2014 and 2016 from 16 to 32 outbreaks.

The parasite is spread by someone who's sick or goes swimming too soon after getting diarrhea. If someone ends up swallowing a mouthful of water contaminated with crypto, it can cause sickness for up to three weeks. The symptoms include watery diarrhea, stomach cramps, nausea, or vomiting.

The parasite is difficult to kill. It can survive up to 10 days in treated water.

KENS 5 talked to the YMCA about the threat of the parasite in pools. Dason Tucker, the senior director of sports and aquatics, said that this is all the more reason why they make sure their pools are safe.

"We test for pH and free chlorine every hour, on the hour, that we're open," he said. "We make sure all of our chemicals are in check."

Tucker said that parents can help prevent crypto from getting into pools.

"Whenever you change your baby's diaper, make sure you transport them and away from the pool water. If your child is feeling ill that day, don't take them to the pool, whatsoever, and wait till that passes," Tucker suggested. "The biggest one, not just with crypto, to help us balance our pools in general, is just showering off before you get into our water."

The CDC noted that it's unclear if the increased outbreaks are due to more cases of crypto or if there are simply better detection tools. For more information on the parasite, click here.